Manufacture of tire-shoes.



HJZ. COBB. MANUFACTURE OF TIRE SHOES. APPLICATION FILED JULY 3.1914. 1 21 1 918, Patented Jan. 9, 1917.

INVENTOR WITNESSES: v 7M5 3 6m, f W

W I 5y AZ/omeyy H. Z. COBB.

MANUFACTURE OF TIRE SHOES.

APPLICATION FILED JULY 3,1914.

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State of Massachusetts,

up in UNI" STATE nanny z. 00312, or wmcnns'rna, MASSACHUSETTS, ASSIGNOR, y manor AND MESNE ASSIGNMENTS, T0 UNITED STATES RUBBER COMPANY, OT! NEW BRUNSWICK, NEW

JERSEY, A'CORPOBATION OE NEW JERSEY.

MANUFACTURE OF TIRE-SHOES.

= Application filed July 3,

To all whom'it may concern:

Be it known that I, HENRY Z. Comma citizen of the lVinchester, in the county of MiddleseX and have invented ceruseful Improvements in the of which the tain new and Manufacture of Tire-Shoes, following is a specification.

In the manufacture of shoes or casings for pneumatic vehicle tires, it is customary to build up the successive layers thereof on .a ring-shaped core or mandrel to which on the exterior the rubber cushion is applied, and then to place the mandrel with its .raw shoe in a mold, assembling a series of such molds held together under suitable pressure in a vulcanizing oven, and therein subjecting them to heat for vulcanizing the tire shoes. Inthis operation it is difficult to in-' sure so close a fit between the raw shoe an the mold as to cause the shoe to completely fill all. theinterstices of the mold andtake a-full imprint therefrom. In order to expand the shoe forcibly within the mold, fluid pressure has been introduced into it and maintained during the vulcanizing; this however is subject to the disadvantage that it is'necessary leading from a source of compressed air or other fluid, as steam, to the respective mold sections, and to maintain these pipes and couplings in non-leaking condition during the vulcanizing period, which ,innpractice involves much difficulty. In my Patent No. 969,181 of August 30, 1910, is set forth a process wherein the-annular mandrel has a liquable rim portion of solidified fluid, such as wax, over which the the shoe is built up, and which when inclosed in the mold and subjected to the vulcanizing temperature, fuses and its pressure is raised by pumping, or it is withdrawn fluid, as water, so as to maintain ahigh fluid pressure within the shoe to expand it against the interior of the mold and hold it so exp anded during the vulcanizing.

My present invention relates to the vulcanizing of the tire shoe while it is expanded within the mold by fluid pressure. 0- cording to my invention, the shoe is built any usual manner upon a suitable then placed .in a mold mandrel; .the shoe is su table construction,

of any ordinary or and-confined therein so asto' prevent the United States, residing n to couple pipes and replaced by. other Specification of Letters Patent.

Patented. Jan. *9, 1917. 1914. Serial No. 848,766.

escape. of fluid pressure from within the shoe. A source of fluid pressure is provided which is individual to the shoe or to each shoe to be vulcanized. This source of pressure is sufficient ,to expand the individual shoe within its mold so as to suitably distend it and force it to conform to the inner face of the mold. At or before the-beginning of the vulcanizing treatment, and before any material vulcanization has occurred, the pressure from such source is liberatedor admitted within the shoe, and it is confined within the shoe during the vulcanizlng. The pressure WVlthlIl the shoe is determined by-the amount of fluid provided at such individual source. As'compared general source to a'plurality of shoes being vulcanized, there is avoided the necessity of making coupling or other connections, a leakage of pressure from one shoe affects only that shoe, and the pressure in each shoe is independent of the pressure in the other shoes undergoing vulcanization. The admission of the pressure to the shoe is determined thermostatically, "so that it occurs when the temperature approaches or attains the vuloanizing temperature and before the rubber has become'sufiiciently vulcanized to lose its plasticity. The gas or vapor under pressure is of determinate volume depending upon the charge previously introduced into the chamber. The chamber is preferably a hollow in the mandrel. Preferably air is forced into the chamber to a given pressure, being confined therein until liberated by the action of the thermostatic means, which is 'a thermostatically actuated valve or a fusible plug. Or a vaporizable liquid such as water may be introduced in measured volume into the chamber, so that on the opening of the thermostatic plug or valve'the Wilcanizing heat will vaporize the water and generate the required pressure within the shoe.

In the preferred mode of practising my invention I proceed as follows: A suitable number of sectional mandrels are provided each comprising preferably three sections for convenience in removing the mandrel from the finished shoe, as is well understood. ,In one or more (preferably such mandrel, are formed cavities or chambers each having an inlet check-valve with the introduction of pressure from one;

two) sections of pands in approaching the i placed in a mold through which compressed air is pumped to the required pressure; for example from to 150 lbs., and each having a thermostatic outlet valve. adapted to open under a temperature of for example l-lO degrees F.

This outlet valve is most simply formed of a plug of Wax, such as paraflin. Or it may be made of a disk of fusible metal fusing at a similar temperature. Or it may be a tappet or other valve having an expansible plug for forcing it open when this plug exvulcanizing temperature. The segments thus charged with compressed air are fitted together to form a complete ring core or mandrel, and on this is built up the the shoe with its outer cushion in any usual manner. This is then which is shaped interiorly to give the proper form and pattern to the exterior of the shoe. The segments of mold are clamped or otherwise pressed together. Usually a considerable number of such molds are assembled and held by one clamping means. The molds are placed in any usual vulcanizing oven or chamber, and thls is heated up to the customary vulcanizing temperature,'and the vulcanizing operatlon is conducted in precisely the ordinary manner. On reaching the prescribed temperature the fusible plugs or other thermostatic valves in the mandrel sections open and permit the compressed air to blow out from the chambers into the shoe, th'ereby lifting the shoe away from the mandrel and expanding it outwardly against the inner face of the mold and holding it there duringthevulcanizing operation. To insure an air-tight joint the usual inner lining of soft-rubber is extended between the inner part or neck of the mandrel and the corresponding faces of the mold, so that this forms a packing to seal the joint between these res ective faces and thereby prevent escape o the compressed air. This process has the important practical advantage that it insures the expanding of each individual shoe by introducing within it the required amount of air or other gas at a determined pressure, and does this without the necessity of establishing or maintaining any pipe connections between the mandrel and the reservoir or other source of compressed fluid. It thus does away with at least one pipe and coupling for each tire shoe being vulcanized. It enables the introduction of compressed fluid to be accomplished previously to the forming of the shoes, and at a time when the mandrel segments are separate and each is easily accessible.

eferring to the accompanying drawings,-Fi ure 1 is a side elevation of a suitable man rel for practisin this invention, one of. the segments thereo being shown in section; Figs. 2 and 3 are fragmentary sections on a larger scale showing respectively construction (not let check-valve e of any liberate the air pressure so as to expand the shoe; Fig. 6 is a cross-section of the mandrel at the location of the fusible plug or valve; Fig. 7 is a section similar to Fig. 5 but showing a mold witha tread portion distinct from the cheek pieces; Fig. 8 is a section showing a modified fusible .valve.

Referring to Fig. 1, the mandrel A is made up of hollow sections a a and a short section b; these are united by a ring 0 within them having any suitable means for attaching the segments to this ring.

herein illustrated) is that set forth in detail in a companion application for patent for mandrel for vulcanizing tire shoes. Each segment a being made hollow has a chamber (Z within it. An insuitable construction isapplied through which to force air or other gas into the chamber d. This valve may be of any usual construction of tire valve, a simple form being that shown, which requires no description. Each seg ment a has a thermostatic outlet valve f preferably of the simple construction shown in F i s. 3 and 4, wherein a cork g, which may e of rubber, is forced tightly into a hole, and a dovetail chamber above it is filled with molten parafiin or other wax to form a fusible plug It. Or as a modified construction a fusible disk 2' (Fig. 8) may be clamped against a seat by introducing a screw. plug j, so that when the temperature fuses the disk it blows out through the ore is.

The mold Bis of usual construction, being of annular form and divided centrally so as to form equal halves as shown in Figs. 4 and 5. Or it may have a supplemental tread mold B confined within a hollow in the cheek molds as shown in Fig. 7. The latter construction is preferablewhen the tread of the shoe is to present salient ribs or projections as in the case of anti-skid tires.

As best shown in Fig. 6 the mandrel has an annular neck portion or inner flange m presenting flat faces on opposite sides flush with the flat side faces of the ring 0. The mold being correspondingly shaped, it is only necessary to extend the inner lining n of the shoe which is of soft rubber inwardly to cover these fiat faces, in order thereby to utilize this lining as a packing for making a tight joint between the mold and the mandrel when the faces of the mold are clamped tightly together by the usual means (not shown). To give further assurance of making an air-tight fit, the neck portion m A suitable formed-with one or temperature to afford the re either of them) are more annular grooves p q, as best shown in Fig. 6, into which grooves the soft rubber of this lining enters under heat and pressure and affords an effectual seal against the escape of the air or other fluid.

Although is that best adapted for carrying out the process which forms the subject of this application, yet other constructions of mandrel and mold maybe used instead. While I prefer the use of compressed air, yet other gases may be substituted, such for example as carbon dioxid. Instead of using air or other fixed gas, vapor may be provided by introducing into the chamber (Z a quantity of water or other vaporizable liquid, choosing a liquid the vapor of which will not affect the rubber of the tire shoe. A prede tel-mined quantity of water will be introduced such that under the vulcanizing temperature the vapor tension will afford the required pressure. v

I claim as my invention 1. In the manufacture of tire shoes, building up a shoe upon a mandrel, confining the shoe and mandrel in a mold, providing an individual source of fluid pressure sufficient to expand said shoe within its mold, forming a pressure tight joint between the mandrel and mold near each edge of the shoe, admitting said pressure between the mandrel and shoe, and vulcanizing the shoe while confining said pressure-within it.

2. In the manufacture of tire shoes, storing in a chamber associated with a mandrel, a charge of fluid adapted under vulcanizing quired pressure, such mandrel having a neck-portion, and

and the ring a (or the construction thus described having thermostatic means adapted to open and liberate such charge at a temperature approaching the vulcanizing temperature, building up the shoe on such mandrel with Gopie of this patent may be obtained for five cents each,

a lining of elastic rubber extended over said neck-portion, placing the mandrel and shoe in a mold fitting the opposite sides of said neck-portion, clamping the mold-sections together so that the extended lining makes a ,tight oint between said neck-portion and mold, and subjecting to perature, opens and der pressure vulcanizing temliberates the stored medium unwithin the shoe to expand the shoe within the mold and hold it expanded during ,vulcanizing.

3. In the manufacture of tire shoes, building up the shoe on a mandrel, providing a source of fluid pressure in thermostatically controlled potential communication with the interior 0 the shoe, placing the mandrel and shoe in a mold, forming a pressure tight joint between the mandrel and mold near each edge of the shoe, applying heat so as to operate thermostatically to admit pressure from said source into the tire shoe, an continuing the heat until vulcanizing is accomplished.

4. In the closing the shoe in a sectional mold with an annular neck portion between the mold sections, a lining of yielding rubber being provided extending over such neck portion, clamping the mold sections together so that such lining makes a tight joint between sai neck portion and mold, liberating within the shoe fluid underpressure from a. source of such pressure individual to the shoe, and sufficient to expand the shoe within its mold and vulcanizing while the shoe is so expanded.

In Witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses. I v

, HENRY Z. COBB. lVitnesses: i

B.{I. MARTIN, 3A. '1. MARTIN.

by addressing the Washington, D. G.

manufacture of tire shoes, in-

"Commissioner of Eatents,

whereby said thermostatic means 

